1. Field
This application relates to tools, wrenches and more specifically to a wrench and a pipe wrench for applying an impacting torque to a workpiece.
2. State of the Art
A pipe wrench with gripping jaws to hold a pipe and a movable vibrating jaw is disclosed in U.S. Pat. No. 4,771,661 (Levchenko). Levchenko has a vibrator in a hollow handle positioned to compress a spring positioned to vibrate a movable jaw. When a workpiece is positioned in the jaws of the wrench, the vibrator and spring cause the movable jaw to vibrate at an electrical frequency.
A slide hammer adapter to convert a locking jaw plier to an impacting device is disclosed in U.S. Pat. No. 4,307,635 (Genova). The slide hammer adapter is designed to replace the standard thumb adjustment screw found in nearly all locking jaw type pliers.
A pipe gripping tong with movable jaws to grip different sizes of pipe is disclosed in U.S. Pat. No. 4,436,002 (Kennington). The movable jaws are elliptically shaped and driven into contact with a pipe by a ring gear. A motor and gear assembly can subsequently apply a torque to the pipe but the device does not have impacting capabilities.
Mechanical fittings such as nuts and bolts and pipe joints can become locked or frozen in place for a variety of reasons, including corrosion of the threads of a pipe joint or nut and bolt. The threads of the pipe joint or nut and bolt may also be distorted or frozen due to temperature extremes, debris in the fitting, or hardening of old sealants or lubricants applied during assembly. In such circumstances, disengagement of the mechanical fittings may be difficult.
When a wrench such as a pipe wrench cannot be operated to deliver sufficient torque to disengage a nut from a bolt or rotate a pipe from a pipe joint or union, workers are understood to sometimes fit an extension over the handle of a conventional pipe wrench to give the user more leverage. The increased lever arm enables the worker to apply more torque to the frozen joint in an attempt to break free the frozen joint. In some cases, however, a pipe may twist and break under the increased torque before the frozen joint disengages. In other cases, a bolt may snap or a nut may be damaged. Various lubricants and penetrating oils can also be applied to the joint to facilitate freeing the frozen joint, but time delays may be involved, and in some cases, such fluids may be ineffective.
There is a need for a wrench capable of effectively applying an impact torque to the exterior of mechanical fittings such as pipe to facilitate relative movement between the parts of a fitting (e.g., nut and bolt) or pipe joint.